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Endothelin (ET) is a potent vasoconstrictor that may be involved in a number of cardiovascular disorders, although its role in normal hemodynamics remains unclear. Twenty-two anesthetized open-chest dogs were instrumented for measurement of systemic and pulmonary hemodynamics, cardiac output, coronary blood flow, and cardiac contractility. Big ET induced peripheral and coronary vasoconstriction, which occurred before significant elevations in plasma ET and which was nearly completely blocked by bosentan, a new nonpeptidic mixed (ETA and ETB) ET receptor antagonist. Bosentan also prevented the peripheral dilatation caused by the specific ETB receptor agonist, sarafotoxin S6c, but did not prevent the peripheral vasoconstriction induced by angiotensin II. Bosentan alone had no significant hemodynamic effect in the normal anesthetized dog, although it did induce a reactive increase in the plasma level of ET-1 and ET-3. This study demonstrates that, despite blocking both ETA and ETB receptors, bosentan alone had no hemodynamic effect, suggesting that ET does not play a major role in the normal hemodynamic status of anesthetized dogs.

BackgroundAspecific scoring systems are used to predict the risk of death postsurgery in patients with infective endocarditis (IE). The purpose of the present study was both to analyze the risk factors for in‐hospital death, which complicates surgery for IE, and to create a mortality risk score based on the results of this analysis.Methods and ResultsOutcomes of 361 consecutive patients (mean age, 59.1±15.4 years) who had undergone surgery for IE in 8 European centers of cardiac surgery were recorded prospectively, and a risk factor analysis (multivariable logistic regression) for in‐hospital death was performed. The discriminatory power of a new predictive scoring system was assessed with the receiver operating characteristic curve analysis. Score validation procedures were carried out. Fifty‐six (15.5%) patients died postsurgery. BMI >27 kg/m2 (odds ratio [OR], 1.79; P=0.049), estimated glomerular filtration rate <50 mL/min (OR, 3.52; P<0.0001), New York Heart Association class IV (OR, 2.11; P=0.024), systolic pulmonary artery pressure >55 mm Hg (OR, 1.78; P=0.032), and critical state (OR, 2.37; P=0.017) were independent predictors of in‐hospital death. A scoring system was devised to predict in‐hospital death postsurgery for IE (area under the receiver operating characteristic curve, 0.780; 95% CI, 0.734–0.822). The score performed better than 5 of 6 scoring systems for in‐hospital death after cardiac surgery that were considered.ConclusionsA simple scoring system based on risk factors for in‐hospital death was specifically created to predict mortality risk postsurgery in patients with IE.

In order to investigate the three-dimensional (3-D) mechanical properties of blood vessels, a new experimental device is described allowing in vitro static and dynamic measurements on segments of arteries with high technical performances. Static tests are applied to sheep common carotid arteries. Considering a thick-walled cylindrical model of orthotropic material under large deformations, a classical 3-D approach based on strain energy density is used to calculate the resulting mechanical behavior law in radial and circumferencial directions and stresses distribution throughout the wall thickness. Results are presented with reference to unloaded and zero-stress initial state thanks to simple measurements of inner and outer circumferences. A particular ratio relating the two main stresses (circumferential and longitudinal) is calculated that put into the forth the progressive modifications in the direction of the predominant stress in the wall and the specific radial location where these changes occur. We observe that this point location is a function of the test conditions of the specimen, i.e., stretching length and level of pressure.

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